Objective: Endometrial hyperplasia is clinically important, because it can lead to abnormal uterine bleeding (AUB) which itself can precede endometrial cancer. Endometrial carcinoma is the most common malignancy of the female genital tract, occurring in about 75%-85% younger, perimenopausal women as endometrial hyperplasia. The treatment is hysterectomy or hormone therapy with progesterone. The aim of this study was, therefore, to compare the effect of levonorgestrel intrauterine device (LNG-IUD) with medroxyprogesterone acetate (MPA) on simple endometrial hyperplasia for fertility preservation. Materials and Methods: Forty women in reproductive age (22-47 years) with AUB with endometrial biopsies confirming simple hyperplasia, were enrolled in this study and then randomly divided into two groups. All patients presented with designed special checklist which was filled with satisfaction. Complete history and physical examination especially blood pressure (BP), body mass index (BMI), breast examination, bimanual vaginal examination, and transvaginal sonography (to measure the thickness of endometrial and exclude the other pathologic lesions) were performed. In the first group, treatment was performed with MPA (20 mg/daily) for ten days and in other group with LNG-IUD was prescribed. After three months, transvaginal sonography and biopsy of endometrium were done. The status of AUB and side-effects of two methods, along with the rate of satisfactory were evaluated. Result: The findings showed the significant differences in the treatment of simple hyperplasia between two groups (LNG-IUD group vs. MPA group) (p < 0.047). Recovery of AUB in the group LNG was enhanced (p < 0.047). Endometrial thickness was reduced in both groups (p < 0.001), but further reduction in LNG group was seen. Also, LNG was tolerated more than MPA. Side-effects of MPA were more and reached significance (p < 0.003). The rate of satisfaction with LNG was higher than MPA and reached significance (p < 0.048). Conclusion: The results of this study show that LNGIUD is more effective than MPA in treatment of simple endometrial hyperplasia and can be helpful in young women who want to preserve their fertilities.